Model Information:
The model was introduced in 1990 and the early releases were made by Kato Japan for Atlas. From 2004 on, the models were made in China and the internals were modified to a more modern mechanism. The Atlas SD7, SD9, SD24 and SD26 all share the same internal mechanism and differ only in their shell details. The modern releases fall under the "Classic" label for the SD7 and SD9 models and "Master" label for the SD24 and SD 26.

The early releases featured the Kato-designed "low friction drive" which had been successfully introduced in their Kato-branded U30C model). This design allowed clean transfer of current from wheels to long copper strips to the chassis and then to the lightboard. This may not sound innovative, as many modern mechanisms use this design today, but in 1990 it was a game-changer. The post-2004 releases are fairly standard "modern" mechanisms featuring a split-frame, dual-flywheels, and magnetic operating knuckle couplers. They run quiet and smooth and can pull 30 or more standard-weight cars.

Earlier DCC factory-equipped versions were fitted with Lenz LE063XF decoders, whereas most recent versions are fitted with NCE N12A0 decoders. The Atlas version of these decoders will respond to manufacturer's address "127" (CV8) i.e. "Atlas Model Railroad Products", though being identical to their original manufacturer's specification.

Prototype History:
An SD9 is a 6-axle diesel locomotive built by General Motors Electro-Motive Division between January 1954 and June 1959. An EMD 567C 16-cylinder engine generated 1,750 horsepower (1.30 MW). This model is, externally, similar to its predecessor, the SD7, but this model, internally, features the improved and much more maintainable 567C engine. The principal spotting feature are the classification lights on the ends of the locomotive, above the number board. The SD9's classification lights are on a small pod, canted outward. The last phase of construction had a carbody similar to the SD18 and SD24, and used two 48-inch (1,219 mm) cooling fans instead of four 36-inch (914 mm) cooling fans.
Four hundred and seventy-one SD9s were built for American railroads and 44 for export.

Road Name History:
The Burlington Northern Railroad (reporting mark BN) was a United States railroad. It was a product of a March 2, 1970, merger of four major railroads - the Great Northern Railway, Northern Pacific Railway, Spokane, Portland and Seattle Railway and the Chicago, Burlington and Quincy Railroad - as well as a few small jointly owned subsidiaries owned by the four.

Burlington Northern operated between 1970 and 1996.

Its historical lineage begins in the earliest days of railroading with the chartering in 1848 of the Chicago and Aurora Railroad, a direct ancestor line of the Chicago, Burlington and Quincy Railroad, which lends Burlington to the names of various merger-produced successors.

Burlington Northern purchased the Atchison, Topeka and Santa Fe Railway on December 31, 1996 to form the Burlington Northern and Santa Fe Railway (later renamed BNSF Railway), which was owned by the Burlington Northern Santa Fe Corporation.*

Brand/Importer Information:
In 1924 Stephan Schaffan, Sr. founded the Atlas Tool Company in Newark, New Jersey. In 1933 his son, Stephan Schaffan, Jr., came to work for his father at the age of sixteen. Steve Jr. built model airplanes as a hobby and frequented a local hobby shop. Being an enterprising young man, he would often ask the owner if there was anything he could do to earn some extra spending money. Tired of listening to his requests, the hobby-store owner threw some model railroad track parts his way and said, "Here, see if you can improve on this".

In those days, railroad modelers had to assemble and build everything from scratch. Steve Jr. created a "switch kit" which sold so well, that the entire family worked on them in the basement at night, while doing business as usual in the machine shop during the day.

Subsequently, Steve Jr. engineered the stapling of rail to fiber track, along with inventing the first practical rail joiner and pre-assembled turnouts and flexible track. All of these products, and more, helped to popularize model railroading and assisted in the creation of a mass-market hobby. The budding entrepreneur quickly outgrew the limitations of a basement and small garage operation. Realizing they could actually make a living selling track and related products, Steve and his father had the first factory built in Hillside, New Jersey at 413 Florence Avenue in 1947. On September 30, 1949, the Atlas Tool Company was officially incorporated as a New Jersey company.

In 1985, Steve was honored posthumously for his inventions by the Model Railroad Industry Association and was inducted into the Model Railroad Industry Hall of Fame in Baltimore, Maryland. In addition, Steve was nominated and entered into the National Model Railroad Association Pioneers of Model Railroading in 1995.